Hi >> This is using GHC 6.10.2 on Windows XP, 2 processors. Is this a known >> bug, or should I try and replicate it? (benchmark is fairly big and >> very dependent on internal things, but I suspect the dramatic >> performance slowdown is unlikely to be related to these bits). > > Yes, what's happening is this: GHC 6.10.2 contains some slightly bogus > heuristics about when to turn on the parallel GC, and it just so > happens that 8 processors tips it over the point where the parallel GC > is enabled for young-generation collections. In 6.10.2 the parallel > GC really didn't help most of the time, but it has undergone a lot of > tuning since then, and in the HEAD things are much better (see the > results from our ICFP submission).
Fantastic! I'll disable parallel garbage collection (I'm fairly certain it won't have any effect for this application). Thanks Neil _______________________________________________ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
